1. Field of the Invention
The present invention relates to a scintillator panel and a radiation image sensor which are used in medical X-ray photography and the like.
2. Related Background Art
While X-ray sensitive films have conventionally been used in medical and industrial X-ray photography, radiation imaging systems using radiation detectors have been coming into widespread use from the viewpoint of convenience and storability of photographed results. In such a radiation imaging system, pixel data caused by two-dimensional radiation are acquired as an electric signal by a radiation detector, and this signal is processed by a processing unit, so as to be displayed on a monitor.
Conventionally known as a typical radiation detector is one having a structure in which a scintillator panel comprising a scintillator formed on a substrate made of aluminum, glass, fused silica, or the like and an imaging device are cemented together. In this radiation detector, the radiation entering from the substrate side is converted by the scintillator into light, which is then detected by the imaging device (see Japanese Patent Publication No. HEI 7-21560).
Meanwhile, though it is necessary for the scintillator panel to have a sufficiently high optical output in order to attain clear images in a radiation detector, the optical output has not been sufficient in the above-mentioned radiation detector.
It is an object of the present invention to provide a scintillator panel having an enhanced optical output, and a radiation image sensor using a scintillator panel having an enhanced optical output.
The scintillator panel in accordance with the present invention comprises a radiation-transmitting substrate, a light-transmitting thin film disposed on the substrate, a scintillator deposited on the light-transmitting thin film, and a protective film covering the scintillator, wherein the light-transmitting thin film has a refractive index lower than that of the scintillator.
Since the light-transmitting thin film having a refractive index lower than that of the scintillator is disposed between the substrate and the scintillator in this scintillator panel, the light generated from the scintillator can be reflected by the light-transmitting thin film to the optical output side, whereby the optical output of scintillator panel can be enhanced.
The radiation image sensor in accordance with the present invention comprises a scintillator panel comprising a radiation-transmitting substrate, a light-transmitting thin film disposed on the substrate, a scintillator deposited on the light-transmitting thin film, and a protective film covering the scintillator, wherein the light-transmitting thin film has a refractive index lower than that of the scintillator; and an imaging device arranged so as to face the scintillator.
In this radiation image sensor, since the light-transmitting thin film having a refractive index lower than that of the scintillator is disposed between the substrate and the scintillator in the scintillator panel, the optical output of scintillator panel increases. As a consequence, the output of radiation image sensor can be enhanced.